Event Driven, meaning that it will automatically react to an internal event

Polled, meaning that it’s periodically executed by the Decanter Scheduler

You can install multiple Decanter Collectors in the same time. In the 1.0.0 release, Decanter provides the following collectors:

log is an event-driven collector. It’s actually a Pax Logging PaxAppender that listens for any log messages and send the log details into the EventAdmin topic.

jmx is a polled collector. Periodically, the Decanter Scheduler executes this collector. It retrieves all attributes of all MBeans in the MBeanServer, and send the JMX metrics into the EventAdmin topic.

camel (jmx) is a specific JMX collector configuration, that retrieves the metrics only for the Camel routes MBeans.

activemq (jmx) is a specific JMX collector configuration, that retrieves the metrics only for the ActiveMQ MBeans.

camel-tracer is a Camel Tracer TraceEventHandler. In your Camel route definition, you can set this trace event handler to the default Camel tracer. Thanks to that, all tracing details (from URI, to URI, exchange with headers, body, etc) will be send into the EventAdmin topic.

Appenders

The Decanter Appenders receives the data harvested by the collectors. They consume OSGi EventAdmin Events from the decanter/collect/* topics.

They are responsible of storing the monitoring data into a backend.

You can install multiple Decanter Appenders in the same time. In the 1.0.0 release, Decanter provides the following appenders:

log creates a log message with the monitoring data

elasticsearch stores the monitoring data into an Elasticsearch instance

jdbc stores the monitoring data into a database

jms sends the monitoring data to a JMS broker

camel sends the monitoring data to a Camel route

SLA and alerters

Decanter also provides an alerting system when some data doesn’t validate a SLA.

For instance, you can define the maximum acceptable number of threads running in Karaf. If the current number of threads is over the limit, Decanter calls alerters.

Decanter Alerters are a special kind of appenders, consuming events from the OSGi EventAdmin decanter/alert/* topics.

As for the appenders, you can have multiple alerters active at the same time. Decanter 1.0.0 release provides the following alerters:

log to create a log message for each alert

e-mail to send an e-mail for each alert

camel to execute a Camel route for each alert

Let see Decanter in action to have details how to install and use it !

NB: for the next Karaf releases, I will add Decanter features repository in etc/org.apache.karaf.features.repos.cfg, allowing to easily register Decanter features simply using feature:repo-add decanter 1.0.0.

We now have a ready to use elasticsearch node, where we will store the monitoring data.

Decanter also provides a kibana feature, providing a ready to use set of kibana dashboards:

karaf@root()> feature:install kibana
We can now install the Decanter Elasticsearch appender: this appender will get the data harvested by the collectors, and store it in elasticsearch:
karaf@root()> feature:install decanter-appender-elasticsearch

The decanter-appender-elasticsearch feature also installs etc/org.apache.karaf.decanter.appender.elasticsearch.cfg file. You can configure the location of the Elasticsearch node there. By default, it uses a local elasticsearch node, especially the one embedded that we installed with the elasticsearch feature.

The etc/org.apache.karaf.decanter.appender.elasticsearch.cfg file contains hostname, port and clusterName of the elasticsearch instance to use:

Karaf monitoring

This collector is event-driven and will automatically listen for log events, and send into the EventAdmin collect topic.

We install a second collector: the JMX collector.

karaf@root()> feature:install decanter-collector-jmx

The JMX collector is a polled collector. So, it also installs and starts the Decanter Scheduler.

You can define the call execution period of the scheduler in etc/org.apache.karaf.decanter.scheduler.simple.cfg configuration file. By default, the Decanter Scheduler calls the polled collectors every 5 seconds.

The JMX collector is able to retrieve all metrics (attributes) from multiple MBeanServers.

By default, it uses the etc/org.apache.karaf.decanter.collector.jmx-local.cfg configuration file. This file polls the local MBeanServer.

You can create new configuration files (for instance etc/org.apache.karaf.decanter.collector.jmx-mystuff.cfg configuration file), to poll other remote or local MBeanServers.

The type property is a free field allowing you to identify the source of the metrics.

The url property allows you to define the JMX URL. You can also use the local keyword to poll the local MBeanServer.
The username and password allows you to define the username and password to connect to the MBeanServer.

The object.name property is optional. By default, the collector harvests all the MBeans in the server. But you can filter to harvest only some MBeans (for instance org.apache.camel:context=*,type=routes,name=* to harvest only the Camel routes metrics).

Now, we can go in the Decanter Kibana to see the dashboards using the harvested data.

Decanter also provides the SLA e-mail alerter to send the alerts by e-mail.

Now, you can play with the SLA checker, and add the checks on the attributes that you need. The Decanter Kibana dashboards help a lot there: in the "Event Monitoring" table, you can see all raw harvested data, allowing you to find the attributes.

What's next

It's just the first Decanter release, but I think it's an interesting one.

Now, we are in the process of adding:

a new Decanter CXF interceptor collector, thanks to this collector, you will be able to send details about the request/response on CXF endpoints (SOAP-Request, SOAP-Response, REST message, etc).

a new Decanter Redis appender, to send the harvested data to Redis

a new Decanter Cassandra appender, to send the harvested data to Cassandra

a Decanter WebConsole, allowing to easily manipulate the SLA

improvement the SLA support with "recovery" support to send only one alert when the check failed, and another alert when the value "recovered"

Anyway, if you have ideas and want to see new features in Decanter, please let us know.